The present invention relates to a self-locking belt roller with a vehicle-sensitive and/or seatbelt-sensitive controllable locking device, the belt roller being provided with a first force limiting device in the form of a torsion rod connected, on the one hand, to the belt winding shaft and, on the other hand, to a special profiled head which is secured to the housing via a controllable blocking element, the belt roller further including an additional deformation element for increasing the resistance to belt withdrawal which is actuated at a location between the belt winding shaft and the profiled head before and/or during the actuation of the torsion rod.
A belt roller with the aforementioned features is described in WO 96/32303. To the extent that additional measures are already described in this publication, they relate to an increase in the restraining forces before the actuation and/or during the actuation of the torsion rod, so that the vehicle occupant still participates during the relatively low initial deceleration of the motor vehicle and later initially upon, for example, contact with an airbag, a reduced restraining force is effected via the actuated torsion rod, whereby this conventional arrangement is representative of the state of the art from which the present invention proceeds in that there is provided, between the belt winding shaft and the profiled head which is lockable onto the circumference of the belt winding shaft, a bendable bolt around the circumference of the belt winding shaft which during a relative movement or relative turning of the belt winding shaft with respect to the profiled head is first initially actuated and bends within a predetermined freedom of movement space before, due to the further relative turning, the force level of the torsion rod is actuated.
In connection with conventional belt rollers, the disadvantage still exists that the disposition of an additional deformation member in addition to the torsion rod requires as a prerequisite a radial overlapping of the belt winding shaft and the profiled head; furthermore, the arrangement of the bending bolt around the circumference of the belt winding shaft so as to permit the predetermined freedom of movement space for its bending is expensive and can be realized only with considerable effort.
The present invention offers a solution to the challenge of providing a belt roller having the afore-described state of the art characteristics which is improved therefrom in a manner such that the arrangement of an additional deformation member is realized in a simpler manner without construction restrictions.
The solution to this challenge is hereinafter described in connection with the advantageous embodiments and variations of the belt roller of the present invention.
The present invention proceeds from the basic concept that the deformation element has its one end engaged or hooked onto the belt winding shaft or onto the profiled head and is configured as a bending element which corresponds to the circumference of the belt winding shaft along its contour and, further, that the bending element has a dimensionally conforming cut out which is engaged by another component in the form of a resistance facilitating element arranged either on the profiled head or the belt winding shaft. In this manner, the present invention relies on the principle of actuating an additional deformation member, as well, in connection with the axially adjacent arranged belt winding shaft and profiled head, in the form of a bending element which is preferably configured as a steel band section and which is seated on the rear side of the belt winding shaft or on the profiled head and which, during a relative turning of the belt shaft and the profiled head, that itself is fixedly connected to the belt winding shaft upon actuation of a blocking element, is drawn through another component in the form of a non-rotating resistance facilitating element. With the thus-effected deformation work, the desired force limitation is performed.
In this connection, a configuration of a force limiting apparatus with a steel band section that is drawn through a resistance facilitating element, the steel band section being basically a bending element, is disclosed in EP 0 791 513 A1.
In accordance with one embodiment of the present invention, it is initially provided that the resistance facilitating element is configured in a non-rotating extension on either the profiled head or the belt winding shaft.
In this connection, in a first alternative embodiment of the present invention, it can be provided that the bending element is hooked onto the rear side of the belt winding shaft adjacent the profiled head and that the extension with the resistance facilitating element is fixedly mounted on the profiled head, whereby the bending element can be disposed in a recess or trough formed in the rear side of the belt winding shaft.
In accordance with a further alternative configuration of the present invention, it is provided that the bending element is suspended on the rear side of the profiled head which is adjacent the belt winding shaft and that the extension is disposed with the resistance facilitating element on the belt winding shaft.
In a further additional configuration of the present invention, it is provided that the bending element is disposed in an extension which is mounted in a non-rotating manner on the profiled head and that the resistance facilitating element is mounted on the belt winding shaft.
It can also be provided that the resistance facilitating element is configured on the rear side of the seat belt winding shaft neighboring the profiled head. The present invention can, in this connection, also be realized such that the resistance facilitating element is configured on a special shaft ring which is connectable with the belt winding shaft.
In a further configuration of the present invention, it is provided that the resistance facilitating element is arranged on the profiled head.
Within the scope of a preferred embodiment of the present invention, it is provided that a security ring is arranged between the belt winding shaft and the profiled head in the form of a roller bushing at a location between the belt winding shaft and the profiled head which effects a reduction of the friction which occurs between the belt winding shaft and the profiled head during a phase of the force limitation. It is provided that the security ring is formed with a rotation preventing axial projection which extends into the respective component and seats therein in order to secure the security ring for its security task. Furthermore, the security ring can include a radial portion operable to prevent displacement movement of the bending element out of its mounted disposition on the respective one of the belt winding shaft and the profiled head, whereby the radial piece is, additionally, a slotted angular element in the plane of the bending element having a slot which receives therein the bending element. In this manner, the security ring effects a sufficient interconnection of the bending element within the scope of its arrangement between the belt winding shaft and the profiled head.
To the extent that an embodiment of the present invention includes the bending element in a form in which the bending element has a uniform dimension along its length, the additional moment created by the bending element is constant. In accordance with a configuration of the present invention, a degressive force path can be adjusted by a pulling through of the bending element through the resistance facilitating element such that the bending element has, in a direction from its hook catch, either a decreasing material strength along its length or a decreasing width along its width; also, a combination of both of these measures is possible.